Thousands of Little Wounds

The thing about trees is that they know what to do. When a leaf loses its color, it;s not because its time is up and it's dying, it's because the tree is taking back into itself the nutrients the leaf's been holding in reserve for it, out thee on the twig, and why leaves change color in autumn is because the tree is preparing for winter, it's filling itself with its own stored health so it can withstand the season. Then, clever tree, it literally pushes the used leaf offset the growth that's coming behind it. But because that growth has to protect itself through winter too, the tree fills the little wound in its branch or twig where the leafs was with a protective corky stuff that seals it against cold and bacteria. Otherwise, every leaf lost would be an open wound on a tree and a single tree would be covered in thousands of little wounds. 

- Artful, Ali Smith